How can I correct this beer material?
Even though you have 'Transmission' bounces set to 12 you are capping the 'Max' bounces to 4, meaning it's never doing 12 bounces. Here I have upped the 'Max' bounces to 6 and the liquid started to let light through: 



If you want the liquid to use all 12 Transmission bounces you will have to set your 'Max' bounces to 12 as well.